Originally part of Plum Township, Monroeville was incorporated from the remaining area of what was then Patton Township. The area took its name from Joel Monroe, the first postmaster.

Settlement began after 1810, when the Old Northern Pike opened for stagecoach travel between Pittsburgh and Philadelphia. The Johnston family, from Annandale in Scotland, was the first family to reside in the area. Descendants operated Johnston Dairy until at least the 1970s.

The first growth took place between Turtle Creek and the Old Stone Church on Monroeville Boulevard. That included the Haymaker Road area, named after Judge John Haymaker, whose home was located there.

Settlement expanded in early 1900s when officials paved roads for automobiles and expanded gas and electric service.

By the mid-1920s, Business Route 22, then known as William Penn Highway, was opened and development began along its route. In October 1949, the five-member Patton Township Municipal Authority formed to bring water to Monroeville.

In January 1952, the first Monroeville officeholders took over from Patton Township. The new municipality was formed to prevent neighboring municipalities from grabbing more land in Monroeville.

The extension of the Parkway East to the Pennsylvania turnpike in 1952 opened Business Route 22 to commercial development. Miracle Mile opened in 1954 and Monroeville Mall in 1969.

Several distinct neighborhoods exist within Monroeville, including Adderly, Patton Heights and Garden City. The school district, now known as Gateway, was organized in 1850 as the Patton Township School District. It became the Monroeville School District after incorporation and Gateway in 1955.

The municipality adopted a home rule charter in 1976.